It has good optical performance ,and also has high mechanical strength and thermal shock strength.Its surface compressive stress is over 90Mpa,the impact strength is 3-5 times of ordinary annealed glass and the flexural strength is 2-3 times of ordinary annealed glass.High intensity means high security.At the same time ,when glass broken ,the stress release instantaneously due to the internal tensile stress and glass breaks into small particles .These light particles have no sharp acute angle and reduces the possibility of human body harm.Tempered glass is subject to the temperature range 250-320°C.